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© Penerbit Universiti Sains Malaysia, 2016

Production and Quality Levels of Construction Materials in Andean Regions: A

Case Study of Chimborazo, Ecuador

*Oscar A. Cevallos1, David Jaramillo2, Carlos Ávila3 and Ximena Aldaz1

1 Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, ECUADOR 2 School of Medicine, Faculty of Health Sciences, National University of Chimborazo,

Riobamba, ECUADOR 3 Facultad de Ingeniería Mecánica, Escuela Politécnica Nacional, Quito, ECUADOR

*Corresponding author: [email protected]

Abstract

An important economic activity in the province of Chimborazo is the manufacture

and production of construction materials such as clay bricks, blocks, pavers and

petrous materials (aggregates). These materials must meet minimum quality

requirements to ensure proper mechanical behaviour and not reduce the lifespan

of civil constructions. In this study, the quality of clay bricks, concrete blocks, paving

bricks and natural aggregates for concrete produced in all the factories of the

province from 2012 to 2015 was assessed. The results obtained were compared with

the quality standards provided by the Ecuadorian Institute of Standardisation (INEN).

All testing procedures for characterisation of physical and mechanical properties

followed the guidelines set by the American Society for Testing and Materials (ASTM)

and the British Standards Institution (BSI). This paper presents the outcomes of the

quality evaluation of construction materials produced in 258 factories located in the

ten districts (cantons) of Chimborazo. The study revealed that paving bricks and

aggregates for concrete performed better than clay bricks and concrete blocks.

The samples of concrete blocks had the highest percentage of non-compliance

specifications and the widest spread of results. Quality problems in the production of

construction materials were found in all the districts of Chimborazo.

Keywords: Quality control, construction materials, physical characterisation,

mechanical testing, Ecuador.

INTRODUCTION

The Construction industry is the largest and most challenging industry worldwide (Liu

et al., 2007; Ofori, 2000; Tucker, 1986;) with prefabricated construction materials

forming the basic raw material used in the construction of buildings and civil

engineering works. These materials include: bricks, concrete blocks used in walls or

slabs, pavers for pedestrian or vehicular roads and petrous materials. These types of

materials offer numerous advantages to professionals in the construction industry; in

fact, the optimization of resources and reduction in costs and construction times

continue to provide conclusive reasons for their extensive utilization (Domone and

Illston, 2010). Construction materials are subject to compliance with technical

specifications and are required to undergo periodic quality controls. Table 1 shows




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the minimum requirements set by the Ecuadorian Institute of Standardization (INEN)

used in this study. According to this classification, C-type bricks are solid handmade

clay bricks, with no perforations or frogs, whereas E-type bricks are hollow clay bricks

that can only be used in non-load-bearing walls and reinforced concrete lightened

slabs. Additionally, the INEN classification considers D-type concrete blocks as blocks

used to build exterior partition walls, with coating or mortar rendering, and E-type

concrete blocks as blocks used to build interior partition walls, with or without

coating or mortar rendering (NTE INEN 0297, 1978; NTE INEN 638, 1993).

The INEN functions as the national technical organization for the quality system of

the country (INEN, 2012). However, problems in the factories of Chimborazo have

been frequent due to either the poor monitoring by producers and/or control bodies

or the constant search for reduced production costs. As such, in 2009, tests

conducted in the Laboratory for Quality Control of Materials (LCCM) of the National

University of Chimborazo (UNACH) on clay brick samples from several private

companies in the province revealed the non-compliance with technical

specifications. In this case, all the samples tested did not meet the recommended

minimum compressive strength and exceeded the maximum permissible absorption

capacity (LCCM report, 2010). Similarly, in 2010, an investigation conducted on

concrete block samples produced in various districts of Chimborazo revealed serious

problems in the quality of the specimens. Once more, E-type concrete blocks failed

to meet the technical specifications for both compressive strength and absorption

capacity (Diaz, 2010).

Undoubtedly, the problems of quality of construction materials can affect the

proper performance of structures and shorten their lifespan. For this reason, quality

requirements are becoming more stringent, primarily in Andean countries like

Ecuador, where earthquakes are common (IGEPN, 2016). The high seismic activity is

mainly due to the clash of the Nazca plate and the South American plate, causing

the subduction of the Nazca plate (Delouis et al., 1996; Yuan et al., 2000). In

Ecuador, earthquakes have been categorized by a seismic zonation map (NEC,

2015), obtained from the results of seismic hazards with a 10% probability of

exceedance in 50 years and a return period of 475 years. The seismic zones defined

on this map consider seismic accelerations of gravity between 0.15 g and 0.50 g,

placing the province of Chimborazo in the seismic zone IV (0.40 g).

The non-compliance with construction quality specifications promotes rapid

deterioration and considerable damage to civil works, resulting in economic losses

(Cnudde, 1991; Formoso et al., 2002). Furthermore, 18% of pathological problems

found in concrete and masonry buildings including: moisture or leaks in walls or slabs,

greatest amount of waste residue, poor strength capacity and premature failure of

concrete elements, and other quality problems present during construction and/or

service phase, are attributed to the quality of building materials (Helene and

Figueiredo, 2003). In Chimborazo, the causes of quality problems found in

construction materials could be attributed to the uncontrolled rise in the number of

producers and factories (INEC, 2011). Here, producers are forced to reduce

production costs to be able to compete with market prices, even though it means a

reduction in the quality of their products. Furthermore, regional governments have




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granted operating licenses to producers of construction materials without requiring

them to provide laboratory reports that verify the quality of their products. All these

factors have contributed to the progressive decline in the quality culture in the

province.

In this study, the results of a quality evaluation of clay bricks, concrete blocks, paving

bricks and concrete aggregates produced in Chimborazo from 2012 to 2015 are

presented. Here, physical characteristics (absorption capacity, acid-soluble portion,

organic impurities, materials finer than 75 m and granulometry) and mechanical

properties (resistance to degradation, compressive strength and flexural strength) of

construction material samples produced in 258 factories located in the ten districts

of Chimborazo were assessed. The level of compliance with the technical

specifications was determined by comparing the test results with the minimum

standards recommended by the governmental body INEN (NTE INEN 0297, 1978; NTE

INEN 638, 1993; NTE INEN 643, 2014; NTE INEN 1488, 2010; NTE INEN 872, 2012). The

outcomes of this analysis provided, among other things, a diagnosis of the current

quality levels and a baseline for promoting new research projects aimed at

improving the quality of construction materials.

Previous studies based on quality control in the construction industry have shown a

substantial improvement in standard requirements when quality management

methodologies were applied (Burati et al, 1991; Koskela, 1992). It is anticipated that

similar studies can be replicated in Chimborazo, and thus specific methodologies for

a Total Quality Control (TQC) and an adequate philosophy to improve production in

the construction industry could be proposed and implemented.

SAMPLING AND TESTING METHODOLOGY

This research was conducted in the province of Chimborazo, which is located in the

Andean region of Ecuador. According to the latest population and housing census

of 2010, its population was of 458,581 inhabitants (INEC, 2011). The capital of the

province is Riobamba, located at 2754 meters above sea level. Chimborazo, along

with the provinces of Cotopaxi, Tungurahua and Pastaza belongs to Zone 3

according to the new territorial organization of Ecuador (Cootad, 2010). The study

included all ten districts of the province: Alausí, Colta, Cumandá, Chambo,

Chunchi, Guamote, Guano, Pallatanga, Penipe and Riobamba, as shown in Figure

1.

Samples of C-type and E-type clay bricks, D-type and E-type concrete blocks,

pedestrian and light traffic concrete paving bricks, and natural aggregates for

concrete were randomly obtained from each factory according to published

methods (NTE INEN 0292, 1977; NTE INEN 639, 2012; NTE INEN 1484, 2010; NTE INEN 695,

2010). The clay brick samples were solid handmade clay bricks, with no perforations

or frogs (C-type bricks), and hollow clay bricks (E-type bricks), with dimensions of 25

cm long, 10 cm wide and 8 cm high. 15 specimens were sampled from each

factory. Since each clay brick specimen of the entire lot has the same opportunity of

being representative in the sample, the specimens were randomly sampled. The




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concrete blocks analysed were hollow sandcrete blocks measuring 40 cm long, 20

cm wide and 10, 15 or 20 cm high, which comprised natural sand, water and binder,

with cement as a binder. Both pedestrian and light-traffic paving bricks were

interlocking concrete pavers, with dimensions of 25 cm long, 25 cm wide and 6 to 10

cm high. Concrete blocks included 6 specimens from each factory, and the analysis

of paving bricks for pedestrian and vehicular traffic comprised 10 specimens from

each factory. Both concrete block and paving brick specimens were sampled by

trained laboratory personnel. The selected specimens were representative of the

whole lot of units from which they were sampled. Samples of fine and coarse

aggregates used in concrete were also obtained directly from open pit and river

mines. Each sample of natural aggregates had an approximate mass of 60 kg, with

which all tests here mentioned for aggregates were performed. Aggregate samples

were collected from conveyor belts. The total sampled amount was placed in

sealed plastic bags that prevented loss or contamination of any part of the sample

during its transport to the testing laboratory.

For factories in Chimborazo, only the aforementioned construction materials have

been produced during the investigation. All the tests were carried out in the UNACH

LCCM laboratory. For clay bricks, compression, three-point bending and absorption

capacity tests were conducted in accordance with ASTM C67-07 (2014), whereas in

the case of concrete blocks, compression and absorption capacity tests were

conducted according to ASTM C140M (2015). The quality of concrete paving bricks

was assessed both in terms of their compressive strength and acid-solubility of the

fine aggregates used in their manufacture. These tests were conducted following

the procedures described in ASTM C140M (2015) and BS 812-119 (1985), respectively.

Aggregate testing, involving sieve analysis, organic impurities determination,

resistance to degradation of small and large-size coarse aggregates by abrasion

and impact in the Los Angeles Machine, followed ASTM methods (ASTM 136M, 2014;

ASTM C117, 2013; ASTM C40M, 2011; ASTM C131M, 2014; ASTM C535, 2012).

Compression and bending tests were conducted using a 3000 kN Matest C089-10N

servo-controlled machine. Bending loads were applied on clay brick specimens

using a three-point bending test device (Figure 2). Sizing characteristics were

determined using Humboldt Manufacturing Company sieves. Statistical analysis was

carried out using the software package R2.14. Results were considered significant

with a level of 5% (95% confidence interval).

A brief description of the methodology of each test is provided below:

a) Compression tests on clay bricks, concrete blocks and paving bricks

Prior to testing, paving brick and block specimens were immersed for 24hr in water

at room temperature, whereas dry bricks were cut in half. Specimens with physical

irregularities on their faces were coated with a layer of sulphur-sand mortar, or

through the aid of wooden plates, a uniform load distribution was achieved. The

compressive strength (C) in MPa was evaluated as follows:




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C = f *P

A Eq. 1

where P is the failure load (Newtons), A is the contact area (mm2), and f is a factor

for thickness-bevel used only in the case of paving bricks (see ASTM C140M-15,

2015). The compressive load was applied at a controlled rate of 15 MPa/min.

b) Three-point bending test on clay bricks

Brick samples were dried in an oven (110 ± 5 °C) for 24hr and then cooled at room

temperature.

Using the three-point bending test device shown in Figure 2, the specimens were

loaded at mid-span until failure. The rate of loading was 8896 N/min. The flexural

strength (MR) was calculated using Eq. 2:

MR =3*P*L

2*b*h2 Eq. 2

where P is the maximum load (Newton), L is the distance between the supports

(mm), b is the length of the specimen (mm), h is the height of the specimen (mm).

c) Absorption capacity test on clay bricks and concrete blocks

The samples were dried at 110 ± 5 °C for 24hr, and the mass (M2) was recorded. The

samples were then immersed for 24hr in distilled water at room temperature, and

after the saturated mass (M1) was recorded, the water absorption percentage (Abs)

was calculated as follows:

Abs =M2 -M1

M1*100

Eq. 3

d) Acid-soluble portion of fine aggregates for concrete

A fine aggregate sample (50 g) and a filter paper (Whatman filter No. 40) were dried

in an oven (110 ± 5 °C) and weighted, with their masses M1 and M2 recorded,

respectively. The dry sample was then mixed with hydrochloric acid (25 mL) and

heated without boiling. The resulting mixture was decanted through the filter paper,

and the solid retained was washed for five times with 50 mL of hot distilled water. The

non-dissolved material was dried at 105 oC, and its mass was recorded (M3).

The percentage of loss in mass due to the effect of acid (%PS) was calculated using

Eq. 4.

%PS =M1- (M3-M2)

M1*100

Eq. 4

e) Abrasion tests on coarse aggregates




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Samples of coarse aggregates (4500 g) were washed and then dried at 110 ± 5 °C.

The samples were subjected to abrasion and impact using 11 steel spheres (abrasive

charges) in the Los Angeles Machine. Results were calculated using equation Eq. 5.

V =

A-B

A*100

Eq. 5

where V is the abrasion resistance (%), A is the initial mass of the sample (g) and B is

the mass of the sample after the test (g).

f) Organic impurities test on fine aggregates

A colourless graduated glass bottle was filled with a sample of fine aggregate (130

mL) and a 3% solution of sodium hydroxide (70 mL). The bottle was then capped,

shaken vigorously and left to stand at room temperature for 24hr. The resulting

coloured solution was assessed according to the Gardner scale as follows:

Gardner colour No. 5 (Grade 1) and Gardner colour No. 8 (Grade 2): low

impurities,

Gardner colour No. 11 (Grade 3): Gardner colour standard

Gardner colour No. 14 (Grade 4) and Gardner colour No. 16 (Grade 5): high

impurities

g) Determination of materials finer than 75 µm in fine aggregates

Samples of fine aggregate (2000 g) were dried at 110 ± 5 °C. The material was then

washed with water using a sieve (No. 200) until the water was clear. The remaining

material was dried again at 110 ± 5 °C. The test result was evaluated according to

Eq. 6.

%P =

A-B

A*100

Eq. 6

where %P is the percentage of material finer than 75 µm, A is the initial dry mass (g)

and B is the dry mass after washing (g).

h) Sieve analysis of aggregates for concrete

Fine (500 g) and coarse aggregates (12000 g) samples were dried at 110 ± 5 °C,

placed on each of a specified series of sieves (ranges provided in NTE INEN 872,

2012) and mechanically agitated for 5 minutes. The grading curve and fineness

modulus were determined and compared with INEN specifications.

RESULTS AND DISCUSSION

Construction materials factories




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Since 2012, a field investigation was conducted to locate and geo-reference all the

factories that produce construction materials in the province of Chimborazo. Table 2

shows the number of factories found in each district according to the type of

materials produced.

In the district of Chambo, along with agriculture, clay brick production is the main

source of income of its population (INEC, 2011). This was evidenced in the 154

factories of construction materials in the district, which represent 98% of all clay brick

factories operating in the province.

Quantitative analysis of the number of factories of construction materials in

Chimborazo is shown in Figure 3. Bricks and concrete blocks production accounts for

87% of all the manufacturing sites, with concrete paving bricks produced in only 5%

of the factories located in the province.

Quality of construction materials

The number of tests performed on the sampled construction materials is reported in

Table 3. Descriptive analysis results for minimum and maximum values of each

physical and mechanical property are outlined in Table 4.

The levels of compliance with the INEN quality requirements obtained in the factories

throughout the province are shown in Figures 4-9.

Of the 258 factories identified in the study, the highest number was present in

Chambo (154 sites). Here, clay brick factories represent the greatest number of

construction materials factories in the province (61%). In these factories, only C-type

solid bricks are produced. In addition to the factories in Chambo, clay bricks are also

manufactured in the district of Alausí. However, both the level of production and the

type of bricks manufactured differ from what occurs in Chambo. In Alausí, only three

factories are involved in the production of clay bricks, and these factories produce

either C-type or E-type hollow bricks (NTE INEN 0297, 1978).

Cumandá and Pallatanga have the least number of manufacturing locations. In

Cumandá, only three factories of paving bricks and concrete blocks were located,

whereas in Pallatanga, only three quarries of concrete aggregates are in operation.

Paver factories located in Cumandá (3 sites) represent only 5% of the total paver

factories in the province (13 sites), with most of the manufacturing locations found

predominantly in Riobamba (8 sites). In fact, after Chambo (154 factories),

Riobamba is the district with the highest number of construction materials factories

(63 sites, Table 2).




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Concrete paving bricks

When analysing the quality of paving bricks, it is also necessary to consider the

standards of the fine aggregates used in their manufacture. Factories producing

pavers in Chimborazo employed fine aggregates, which, in all cases, were

compliant with the technical specifications related to the maximum mass of acid-

soluble material extracted (Figures 4a and 5b). For instance, the fine portion (passing

a 5 mm test sieve and retained by a 600 m test sieve) of the aggregate samples

had no acid-soluble materials higher than 25%.

For compressive strength testing, the results show that 85% of the evaluated factories

produced paving bricks with suitable strengths. Regarding pedestrian paving bricks,

most of the tested specimens (36 specimens) show strength values between 20 and

48 MPa, with only four specimens exhibiting poor compressive strength results (13 - 19

MPa). For vehicular paving bricks, all specimens (90 specimens) met the technical

specification for compressive strength. Overall, most of the specimens (73

specimens) exhibited strengths between 35 and 50 MPa.

Clay bricks

The INEN 0297 (1978) standard specifies that C-type ceramic bricks must have a

minimum compressive strength of 8 MPa, a minimum flexural strength of 2 MPa and

a maximum absorption capacity of 25% (Table 1). Regarding the brick samples

analysed (157 factories), 76 factories produced clay bricks that met the

specification for compression strength, 124 factories exhibited flexural strengths

higher than 2 MPa and 135 factories met the water absorption criteria (Figures 4c,

6a, 6c and 6e). On the other hand, serious problems were found with the quality of

E-Type hollow bricks produced in Alausí (Figures 6b and 6d), with all specimens

failing to meet the strength specifications recommended in the INEN standards

(Table 1). In terms of compressive and flexural strength, the results obtained were 1.4-

1.6 MPa and 0.3-0.6 MPa, respectively. Therefore, E-type bricks only met the

specification related to their absorption capacity, as shown in Figure 6f.

Concrete blocks

Concrete blocks and fine aggregates are the most common construction materials

produced in Chimborazo, with manufacturing sites found in 7 districts throughout the

province. The concrete blocks produced showed the lowest levels of quality in all

the factories tested, with the only exception being the district of Penipe (Figures 7a

and 7c). The NTE INEN 638 (2009) and NTE INEN 643 (2014) standards specify that the

minimum compressive strengths of D-type and E-Type concrete blocks should be 2.5

and 2 MPa, respectively. However, the compression tests results revealed that only

14% of D-type blocks and 17% of E-type blocks exhibited strengths greater than or

equal to the minimum strength specification. From a total of 195 D-type blocks

tested, only 31 specimens exhibited compressive strengths above the reference




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value (Figure 10a). Similar results were obtained from testing E-type concrete blocks,

where only 23 specimens (from 138 specimens) demonstrated appropriate quality

levels (Figure 10b). For water absorption capacity, 87% of factories failed to meet

the mandatory criteria. In this case, 159 D-type and 121 E-type concrete block

specimens obtained water absorption values of 15 to 35%.

Since the types of blocks studied were cast using cement as a binder, quality

problems, particularly those observed in E-Type blocks, might be well related to the

quality of the cement used. However, this appears unlikely, since in Ecuador, the

cement used for concrete production meets the requirements specified in ASTM

C150, 2007 and NTE INEN 152, 2012. The cement produced in Chimborazo has been

classified as a pozzolanic portland cement (IP type), meeting quality specifications

and being subject to frequent inspections as reported by the manufacturer

(Chimborazo Cement, 2016). As highlighted by Diaz (2010), the quality of E-type

concrete blocks is not affected by the quality of cement; furthermore, if a mixture

with appropriate proportions of its components is used, the block samples will

exceed minimum quality requirements.

In contrast, the results obtained in this study indicated that concrete pavers

exhibited higher levels of quality compared to concrete blocks. The production of

concrete blocks with poor quality appears to be a common problem in developing

countries (Baiden and Tuuli, 2004; Florek, 1985; Usman and Gidado, 2013; Samson et

al., 2002; Anosike and Oyebade, 2011; Osarenmwinda and Edigin, 2010 ). Causes

include an absent quality control program and poor monitoring by producers,

deliberate reduction in the amount of cement in concrete mixes to lower costs, lack

of staff in charge of quality control with formal training, the use of non-appropriate

production techniques or equipment and a failure to comply to recommended

production standards related to moulding, curing and batching methods.

According to Anosike and Oyebade, (2012), despite the existence of a quality

standard in countries like Nigeria, where the proportions of mixtures or water-to-

cement ratios are specified, the lack of penalties for those who do not meet quality

specifications has given producers the leeway to produce blocks of poor quality for

commercial use.

Natural aggregates for concrete

All quarries of fine aggregates had no problems associated with the presence of

organic impurities, apart from those quarries located in Riobamba (Figure 8b).

Considering the granulometric analysis results, concrete aggregates with an

adequate particle size distribution were found in 60 % of fine aggregate quarries (12

sites) and 67% of coarse aggregate quarries (10 sites).

It should be noted that several factories of fine and coarse aggregates had

problems in meeting the standard requirements for granulometry and materials finer

than 75 m; in particular were the factories located in Alausí, Guano, Pallatanga

and Riobamba, which showed the lowest levels of quality in the province (Figures




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8a, 8c and 9a). However, if all the quarries located in Chimborazo are considered,

80% of the fine aggregate samples (16 quarries) had no problems with materials finer

than 75 m, thus fulfilling the INEN standard; in this case, percentages of materials

finer than 75 m were below 5%, with the average of results found in the order of

3.9%.

In contrast, all coarse aggregate quarries produced materials with a suitable

abrasion resistance value (Figure 9b). For instance, every coarse aggregate sample

had no significant abrasion problems of its particles, with the abrasion results being

only 3.6-19.8% (<< 50%), as shown in Figure 11.

CONCLUSIONS

Concrete paving brick factories achieved the highest levels of quality in their

products, followed by quarries producing fine and coarse aggregates. However, as

graphically illustrated (Figures 4-9), all districts of the province of Chimborazo

revealed quality problems in the construction materials samples analysed during this

study. The highest percentage of non-compliance and the widest spread of results

were recorded for concrete block samples. Furthermore, the highest number of

factories that need to improve the quality of its building products was found in the

district of Chambo. In Ecuador, non-industrial production of construction materials

such as bricks, concrete blocks, pavers and concrete aggregates is the main source

of income for many families. Unfortunately, this has resulted in the rapid and

uncontrolled commercialization of such materials leading to numerous quality

problems, as evidenced by the findings of this work. These problems were observed

primarily in the production of concrete blocks and clay bricks.

Until 2011, most factories involved in the production of construction materials in

Chimborazo had never monitored the quality of their production and were unaware

of the technical requirements that had to be met. Despite the many quality

problems found, the study reveals the presence of some factories that meet the

technical specifications of their products, in terms of physical and mechanical

properties of the samples analysed. The results of the tests conducted were passed

on to each manufacturer through lab reports. Currently, 100% of the construction

material factories in Chimborazo, operating from 2012 to 2015, know what technical

specifications have to be met and monitor the quality of their production.

The findings obtained in this study have enabled the authors to promote a new

research project (Cevallos et al., 2014) aimed at establishing the causes of quality

problems that are commonly seen, particularly in clay bricks and concrete blocks

produced in Chimborazo. Government agencies dedicated to the quality control of

construction materials and producers have been informed of the results of these

studies. Nevertheless, the necessary change in the quality culture of the population

remains unclear. Government agencies are urged to implement new reforms to laws

and ordinances, so that the quality requirements for producers of construction

materials in the province become stricter. Regular training programs along with




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routine production laboratory reports should become mandatory before any

producers of construction materials have their operating licenses renewed.

Further studies should be conducted in Chimborazo to know the exact impact of the

work conducted by the authors on improving the quality of the construction

materials assessed in this investigation.

ACKNOWLEDGEMENT

The authors would like to thank the support provided by the funding body

SENPLADES [$282.054,50 USD] to execute the research project “Database for Quality

Control of construction materials produced in the Province of Chimborazo”, which

validated the work in this article.

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Instituto ecuatoriano de Normalización (INEN). (1978). NTE INEN 0297:1978: Ceramic

bricks – Requirements (in Spanish). Available at:


Instituto ecuatoriano de Normalización (INEN). (1993). NTE INEN 0638:1993: Hollow

blocks of concrete – Definitions, Classification and General Conditions (in Spanish).

Available at: https://law.resource.org/pub/ec/ibr/ec.nte.0638.1993.pdf.

Instituto ecuatoriano de Normalización (INEN). (2010). NTE INEN 695:2010:

Aggregates – Sampling (in Spanish). Available at:

https://law.resource.org/pub/ec/ibr/ec.nte.0695.2010.pdf

Instituto ecuatoriano de Normalización (INEN). (2010). NTE INEN 1484:1986: Concrete

paving bricks – Sampling (in Spanish). Available at:


Instituto ecuatoriano de Normalización (INEN). (2010). NTE INEN 1488:1986: Concrete

paving bricks – Requirements (in Spanish). Available at:


Instituto ecuatoriano de Normalización (INEN). (2012). La Institución: Misión and

Visión. Available at: http://www.normalizacion.gob.ec/la-institucion/ [Accessed on 8

May 2015].

Instituto ecuatoriano de Normalización (INEN). (2012). NTE INEN 152:2012: Cement

Portland – Requirements (in Spanish). Available at:



blocks of concrete – Sampling, Inspection and Acceptance (in Spanish). Available

at: https://law.resource.org/pub/ec/ibr/ec.nte.0639.2012.pdf.

Instituto ecuatoriano de Normalización (INEN). (2012). NTE INEN 872:1982:

Aggregates for concrete – Requirements (in Spanish). Available at:



blocks of concrete – Requirements (in Spanish). Available at:

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content/uploads/downloads/2014/02/nte_inen_643.pdf

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Sismos del Ecuador. Available at: http://www.igepn.edu.ec/sismos [Accessed on 02

Feb 2016].

Instituto Nacional de Estadísticas y Censos (INEC) (2011). Population Census results

(in Spanish). Available at:

http://www.inec.gob.ec/cpv/?TB_iframe=true&height=450&width=800%27%20rel=slb

ox,%202012. [Accessed on 05 Jun 2015].




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Koskela, L. (1992). Application of the New Production Philosophy to Construction.

Technical Report No. 72, CIFE Department of Civil Engineering, Stanford University.

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ensayos de Laboratorio. LCCM Report No. 01-10. Ecuador, Riobamba: Universidad

Nacional de Chimborazo.

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and insurance in Chinas construction industry – an empirical study. Industrial

Management and Data Systems, 107(3): 382–396.

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– Diseño Sismoresistente. Available at: http://www.habitatyvivienda.gob.ec/wp-

content/uploads/downloads/2014/08/NEC-SE-DS.pdf.

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Lessons from Various Countries. Conference Paper, Challenges Facing Construction

Industries in Developing Countries, 2nd International Conference on Construction in

Developing Countries: Challenges facing the construction industry in developing

countries 15-17 November 2000, Gabarone, Botswana.

Osarenmwinda, J.O., Edigin, S.A. (2010). Quality Assessment of Hollow Sandcrete

Blocks Produced by Block Moulding Factories in Benin City. International Journal of

Science and Technological Research, 7(1) & (2): 19–24.

Samson, D., Elinwa, A.U., Ejeh, S.P. (2002). Quality Assessment of Hollow Sandcrtee

Blocks. Nigeria Journal of Engineering Research and Development, 1(3): 37–46.

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Management in Engineering, 2(3): 148–156.

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Produced by Block Moulding Factories in Gombe Metropolis. Journal of Science,

Technology & Education, 2(1): 61–65.

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(2000). Subduction and collision processes in the Central Andes constrained by

converted seismic phases. Nature, 408: 958–961.

LIST OF TABLES & TABLE CAPTIONS

Table 1. Technical specifications for construction materials in Ecuador provided by

the Ecuadorian Institute of Standardisation (INEN)

Construction

material Type Characteristic

Minimum

requirement

Clay bricks C Compressive strength* 8 MPa.




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Flexural strength* 2 MPa.

Absorption capacity* 25%

E

Compressive strength* 4 MPa.

Flexural strength* 3 MPa.

Absorption capacity* 18%

Concrete blocks

D Compressive strength^ 2.5 MPa.

Absorption capacity^ 15%

E Compressive strength^ 2 MPa.

Absorption capacity^ 15%

Paving bricks

Pedestrian Compressive strength† 20 MPa

Light traffic Compressive strength† 30 MPa-40 MPa.

Fine

aggregates Acid-soluble portion 25%

Natural

aggregates for

concrete

Fine

aggregates

Organic impurities

Colour Gardner No

11 - Grade 3

(Colour standard)

Materials finer than 75

µm 5%

Sieve analysis

Size Passing

(%)

9.5 mm 100

4.75 mm 95 to 100

2.36 mm 80 to 100

1.18 mm 50 to 85

600 μm 25 to 60

300 μm 10 to 30

150 μm 2 to 10

Coarse Resistance to

degradation by 50%




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aggregates abrasion and impact

Sieve analysis

Size Passing

(%)

63 mm 100

53 mm 95 to 100

26.5 mm 35 to 70

13.2 mm 10 to 30

4.75 mm 0 to 5

Note 1: ^average of three specimens; *average of five specimens; †average of

ten specimens.

Note 2: Data extracted from: NTE INEN 0297 (1978); NTE INEN 638 (1993); NTE

INEN 643 (2014); NTE INEN 1488 (2010); NTE INEN 872 (2012).

Table 2. Construction materials factories located in the province of Chimborazo.

District Paving

bricks

Aggregates for

concrete

Concrete

blocks

Clay

bricks TOTAL

Alausí 0 3 6 3 12

Colta 1 1 5 0 7

Cumandá 2 0 1 0 3

Chambo 0 0 0 154 154

Chunchi 0 0 0 0 0

Guamote 0 1 3 0 4

Guano 1 2 5 0 8

Pallatanga 0 3 0 0 3

Penipe 1 2 1 0 4

Riobamba 8 10 45 0 63

Sum 13 22 66 157 258




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Table 3. Quality control assessment on construction materials from factories in

Chimborazo.

Construction

material Type of Test performed

Number of

tested

specimens

Clay bricks

Compressive strength 785

Flexural strength 785

Absorption capacity 785

Concrete blocks Compressive strength 396

Absorption capacity 396

Paving bricks Compressive strength 130

Acid-soluble portion 13

Fine aggregates for

concrete

Organic impurities 20

Materials finer than 75 µm 20

Sieve analysis 20

Coarse aggregates

for concrete

Resistance to degradation by

abrasion and impact 15

Sieve analysis 15

TOTAL 3380

Table 4. Descriptive analysis of physical and mechanical properties for construction

materials analysed in Chimborazo.

Building materials Range of analysis Frequency

Clay bricks

Compressive strength

7,3 MPa-7,9 MPa Highest 64

17,8 MPa-18,4 MPa Lowest 1

Flexural strength





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Absorption capacity

20%-21% Highest 132

4%-5% Lowest 1

Concrete blocks

Compressive strength - Concrete blocks (D-type)



Absorption capacity - Concrete blocks (D-type)

24%-26% Highest 42

3%-5% Lowest 1

Compressive strength - Concrete blocks (E-type)



Absorption capacity - Concrete blocks (E-type)

22%-24% Highest 43

10%-12% Lowest 2

Concrete paving bricks

Compressive strength - Pedestrian paving bricks

20 MPa-25 MPa Highest 9

13 MPa-15 MPa Lowest 1

Compressive strength - Traffic paving bricks

38 MPa-39 MPa Highest 17

30 MPa-31 MPa Lowest 2

Acid-soluble portion - Fine aggregates

11%-12% Highest 30

13%-14% Lowest 10

Fine aggregates Organic impurities




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Colour - Gardner # 5 Highest 18

Colour - Gardner # 8 Lowest 2

Materials finer than 75 µm

2,8%-4,2% Highest 9

7,3%-8,7% Lowest 1

Sieve analysis

2,36 mm Highest 9

300 μm Lowest 1

Coarse aggregates

Resistance to degradation by abrasion and impact

8%-12% Highest 7

18%-22% Lowest 1

Sieve analysis

25 mm Highest 10

12,5 mm Lowest 1

LIST OF FIGURES & FIGURE CAPTIONS




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